Well... I'm certainly no expert with regard to this, although I think I probably have some complex PTSD myself.
When I think of PTSD versus cPTSD I think that PTSD is a response to a particular experience, where cPTSD is a response to an accumulation of experiences over time. (I don't know if that's at all accurate though.)
Here are links to 2 articles, from PC's archives, one that discusses PTSD & one on cPTSD:
Posttraumatic Stress Disorder (PTSD)
Complex PTSD | Psychotherapy Matters